The wonderful world of physics: Experiments you can try at home

[Oliver Price | Contributing Writer]

There’s a common myth about science that it’s inaccessible, that only boffins with three inch thick horn-rim glasses and lab coats can ever actually do science. You’d be forgiven for thinking this, considering the massive publicity of multi-million pound projects such as CERN’s Large Hadron Collider and the the many stories from a certain tabloid newspaper about what does and does not cause cancer.

But hope is not lost for those of us without 12 PhDs or million pound budgets. There are some experiments you can do at home  (or in the garden if you don’t want to make a mess) to demonstrate some basic scientific principles.

Did you know that all objects fall at the same speed?

First.experiment

This one is fairly easy to prove. Get a light ball and a heavy ball, and drop them from the same height. They should hit the ground at the same time.

Why? Because on planet Earth we have a constant acceleration due to gravity (g) of 9.81 m/s2 which is the result of by the mass and radius of the Earth, as well as Sir Isaac Newton’s gravitational constant (G) which is constant throughout the universe. Therefore, irrespective of the mass of the falling objects, any object will fall at the exact same speed.

“But a feather falls a lot slower than a golf ball!” you may say. This is true, but only because of the air resistance produced by the feather, whereas a ball would have very little air resistance. If you dropped a feather and a bowling ball in a vacuum (somewhere with no air), they would hit the ground at the exact same time. Here is an excellent Brian Cox video

Did you know that you can build yourself an electromagnet?

Second Experiment

Grab yourself a battery, an insulated copper wire with stripped ends, an iron nail, and a few paper clips. You need to wrap the wire around the nail and attach the ends of it to either end of the battery. Watch out for the battery getting hot. Your nail will become magnetic and be able to pick up the paper clips. Try adding more coils to the nail and see how far away you can attract the paper clips.

This works because electricity and magnetism are two intrinsically linked forces. An electric current can induce a magnetic field, and a magnetic field can also induce an electric current. This is actually how electric transformers on the National Grid work; a coil induces an current in a differently sized coil to step the voltage either up or down.

Did you know that you can retrieve spilled wine back into the glass?

Third experiment

To do this, you will need your spilled wine (or water, if you don’t want to waste precious booze) on a paper plate, a book of matches, a lighter, and a glass.

Stand the book of matches up on the plate of liquid with the matches showing. Light the matches, and put the glass on top. The liquid will be, as if by magic, sucked into the glass. Alcohol saved! And smokey. It’s probably not a good idea to drink it.

So why does this happen? When you light the match it burns the oxygen in the air in the glass creating a partial vacuum. This means that the pressure inside the glass is a lot lower than the pressure outside the glass. The higher pressure pushes the wine in so as to replace the volume where the air used to be. This is what suction is.

It’s essentially a makeshift vacuum cleaner. And you can use it as a bar trick to get free drinks!

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Everyone can do science, and understand it. It’s not a giant monolithic abstract concept. All science is done in the exact same way as these experiments. You have an idea, and test it to see if it’s true. That’s why science works, so when you hear about an amazing scientific discovery, you know that the people responsible for it have tested it, and that other people have tested it, and even more have repeated it and got the exact same result, just like you will with these experiments!

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The wonderful world of physics: Experiments you can try at home